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Hey All... having to revive my old thread...
So I eventually did a leakdown test on my car.. found that it was indeed bent valves all along the exhaust side of the new head. Incredibly infuriating because the ebay seller had said the donor car didn't have any engine issues and the head was ready for install. I haven't had to swap heads on a car before although I've done head gaskets many times... so I wouldn't say i had the know-how to really check this kind of thing when i got the head, and the head's valves didn't visually look bent at all. Anyway.
I dropped the head again, swapped and lapped valves. Put the head back on and did a leakdown check twice... right after torquing everything and after the engine was back together and running. Both times, the head has passed the leakdown check.
Here's the problem. I'm still getting a misfire.
I've been looking at what feels like EVERYTHING. Swapping coils again from bank to bank, checking and moving coil grounding, looked for vacuum leaks with a smoke machine. Checking it on durametric. I even pulled the SAI system off and blew through it to see if maybe it was leaking... I just can't figure it out.
The cam angles are still really close, like -2 deg and -3 deg. The RKAT values are low and kinda close--1.4 and .8. I was thinking maybe it's a cam timing issue... but the cam deviations are so close and exhaust cam is set with my timing tool... so how could it really be that far off?
It doesn't really misfire when its cold, but as it warms up, it's all on cyl 4-6 and just seems random. Like maybe once every 20-30 sec, but then occasionally it will just misfire every other second for maybe 20 sec in a row. All of this just while its at Idle. I don't have a CEL, but it shows on the durametric and I can hear a very slight burble in the exhaust. Car drives actually really well.
As I type this, I've covered my old coils with vulcanizing silicone gasket sealer because i did find little cracks in the coils, but its on all the coils, not just the coils for 4-6. So really if its the coils, I think all the cylinders would be misfiring. If this doesn't fix it, I think I'll buy 6 new coils and 2 new oxygen sensors just to throw money at the thing.
Alternatively I haven't done much to check the injectors or anything. I might look there as well, but that seems so unlikely. What else can I possibly be missing? Any recommendations on how to check the injectors without buying a set of 6? I feel like I'm going crazy here.
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